如何获得boto3集合的大小？ [英] How do I get the size of a boto3 Collection?

问题描述

我一直使用的方式是将Collection转换为一个列表并查询长度：

The way I have been using is to transform the Collection into a List and query the length:

s3 = boto3.resource('s3')
bucket = s3.Bucket('my_bucket')
size = len(list(bucket.objects.all()))

但是，这会强制整个集合的解析，并避免使用集合的好处。有没有更好的方法来做这个？

However, this forces resolution of the whole collection and obviates the benefits of using a Collection in the first place. Is there a better way to do this?

推荐答案

这些对象是AWS S3的限制（请参见 https://forums.aws.amazon.com/thread .jspa？messageID = 164220 ）。

There is no way to get the count of keys in a bucket without listing all the objects this is a limitation of AWS S3 (see https://forums.aws.amazon.com/thread.jspa?messageID=164220).

获取对象摘要（HEAD）没有获得实际数据，所以应该是一个相对便宜的操作，如果你只是舍弃该列表，然后你可以这样做：

Getting the Object Summaries (HEAD) doesn't get the actual data so should be a relatively inexpensive operation and if you are just discarding the list then you could do:

size = sum(1 for _ in bucket.objects.all())

这将给你没有构造列表的对象数。

Which will give you the number of objects without constructing a list.

这篇关于如何获得boto3集合的大小？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！